How to remove line break before certain notepad++ character?

Question

Regular Expressions

Hello, there was a problem with the base, it now looks like this:
question 1
: answer 1
question 2
: answer2
question 3
: answer3
How can I use a regular expression or tools to carefully remove the line break before the characters: remove the line break so that the base looks like this:
question 1: answer1
question 2:answer2
question 3:answer3
Googled, did not find anything specifically on my problem

Answer 1

Search pattern \r?\n:
Replacement string :
https://regex101.com/r/zV0DEE/1

Answer 2

It can be simpler - ctrl + a and then ctrl + j